四川汶川7.8级地震

刚刚知道，四川汶川地震，分别7.8和5.4（再刷屏变7.8和6.0了）。

查了美国地理勘测局（ United States Geological Survey’s (USGS) Earthquake Hazards Program）网站，看到最详尽的数据：

放大亚洲局部：

再次点击具体描述数据出来，貌似离成都最近，距四川成都90公里范围：

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Earthquake Details

Magnitude	7.8
Date-Time	Monday, May 12, 2008 at 06:28:00 UTC Monday, May 12, 2008 at 02:28:00 PM at epicenter Time of Earthquake in other Time Zones
Location	31.119°N, 103.258°E
Depth	10 km (6.2 miles) set by location program
Region	EASTERN SICHUAN, CHINA
Distances	90 km (55 miles) WNW of Chengdu, Sichuan, China 150 km (95 miles) WSW of Mianyang, Sichuan, China 360 km (220 miles) WNW of Chongqing, Chongqing, China 1545 km (960 miles) SW of BEIJING, Beijing, China
Location Uncertainty	horizontal +/- 5.9 km (3.7 miles); depth fixed by location program
Parameters	NST=216, Nph=216, Dmin=>999 km, Rmss=1.43 sec, Gp= 29°, M-type=moment magnitude (Mw), Version=8
Source	USGS NEIC (WDCS-D)
Event ID	us2008ryan

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Earthquake Details

Magnitude	5.4
Date-Time	Monday, May 12, 2008 at 07:34:42 UTC Monday, May 12, 2008 at 03:34:42 PM at epicenter Time of Earthquake in other Time Zones
Location	31.278°N, 103.799°E
Depth	10 km (6.2 miles) set by location program
Region	EASTERN SICHUAN, CHINA
Distances	70 km (45 miles) NNW of Chengdu, Sichuan, China 95 km (60 miles) WSW of Mianyang, Sichuan, China 325 km (200 miles) NW of Chongqing, Chongqing, China 1485 km (920 miles) SW of BEIJING, Beijing, China
Location Uncertainty	horizontal +/- 13.5 km (8.4 miles); depth fixed by location program
Parameters	NST= 28, Nph= 28, Dmin=>999 km, Rmss=0.46 sec, Gp= 86°, M-type=body magnitude (Mb), Version=6
Source	USGS NEIC (WDCS-D)
Event ID	us2008ryat

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发文后更新：

刚刚写时候看到的页面是7.5，几分钟后刷屏变成7.8.

震央的图实时不断变化，这是N分钟前的截屏, 7.5级：

N分钟后刷新成7.8了：

北京时间16点50分再次刷新，图的样子又变了，为什么呢？

有这个专业的同学麻烦给解答一下：

附链结：

全世界最新地震列表 （中国四川成都的两次现在排在1、2位）